Backports of numpy#29842, numpy#29845, numpy#29846, numpy#29847.

commit fe3a74c
Author: Joren Hammudoglu <jhammudoglu@gmail.com>
Date:   Wed Oct 1 03:56:24 2025 +0200

    TYP: Fix incompatible defaults in ``polyfit``, ``histogram``, and ``histogramdd`` (numpy#29847)

    The default values weren't assignable to the types of the parameters.

commit 2342cb0
Author: Joren Hammudoglu <jhammudoglu@gmail.com>
Date:   Wed Oct 1 03:54:37 2025 +0200

    TYP: Fix signatures of ``linalg.matmul`` and ``linalg.outer`` (numpy#29846)

    This fixes several issues in np.linalg.outer (positional-only params, a misplaced out=... param, and an orphanced -> _ArrayT), and also fixes linalg.matmul parameters to be positional-only.

    I also snuck in an an additional overload that improves the return type if both input array-likes have the same dtype.

commit a8d7d13
Author: Joren Hammudoglu <jhammudoglu@gmail.com>
Date:   Wed Oct 1 03:53:00 2025 +0200

    TYP: Add missing ``rtol`` kwarg to ``linalg.pinv`` (numpy#29845)

    Apparently it was added in 2.0.0, but was missing from the stubs.

commit d9f83ec
Author: Joren Hammudoglu <jhammudoglu@gmail.com>
Date:   Wed Oct 1 03:47:57 2025 +0200

    TYP: Fix ``generic.__new__`` return type (numpy#29842)